Method for dispensing dry granular materials

ABSTRACT

A material dispensing system for agricultural pesticides and chemicals. The system uses distributed processing with a main controller and a plurality of sub-controllers to control pesticide metering devices. The metering devices are attached to a pesticide container.

This application is a continuation of application Ser. No. 08/591,336,filed Jan. 25, 1996, now abandoned, which is a Divisional application ofSer. No. 08/172,367, filed Dec. 22, 1993 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to material delivery systems forgranular or solid pesticides and more particularly to materialdispensing systems using distributed processing.

In markets requiring the usage of chemicals, often hazardous substances,the Environmental Protection Agency and other regulatory bodies areimposing stricter regulations on the transportation, handling,dispersion, disposal, and reporting of actual usage of chemicals. Theseregulations, along with public health concerns, has generated a need forproducts that address these issues dealing with proper chemicalhandling.

To reduce the quantity of chemicals handled, the concentration of thechemical, as applied, has been increasing. This has raised the cost ofchemicals per unit weight and has also required more accurate dispensingsystems. For example, typical existing systems for agriculturalpesticide dispensing use a mechanical chain driven dispenser. Normalwear and tear on these mechanical dispensers can alter the rate ofpesticide applied by as much as 15%. For one typical chemical, Force®, apyrethroid type insecticide by ICI, an over-application rate of 15% canincrease the cost of the insecticide by $750 over 500 acres.

Since many of the current pesticide systems are mechanical systems, anyrecord keeping and reporting must be kept manually.

The foregoing illustrates limitations known to exist in present materialdelivery systems. Thus, it is apparent that it would be advantageous toprovide an alternative directed to overcoming one or more of thelimitations set forth above. Accordingly, a suitable alternative isprovided including features more fully disclosed hereinafter.

SUMMARY OF THE INVENTION

In one aspect of the present invention, this is accomplished byproviding a method for dispensing dry granular material from a movingagricultural implement including the steps of determining a desireddispensing rate; generating command data consistent with the desireddispensing rate to control the actuation of a metering device todispense said dry granular material; measuring the ground speed of theagricultural implement; modifying the command data to account for theground speed; receiving stored calibration data for said metering devicefrom an electronic storage device; modifying the command data to accountfor the calibration data of the metering device; and actuating themetering device in response to the command data.

The foregoing and other aspects will become apparent from the followingdetailed description of the invention when considered in conjunctionwith the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a simplified diagram showing a material dispensing systemincorporating the present invention;

FIG. 2 is a side view of one embodiment of an electromechanicaldispensing device for use with the material dispensing system shown inFIG. 1; and

FIG. 3 is a schematic diagram of the distributed controller system forthe material dispensing system shown in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a simplified diagram of a planter 20 incorporating adistributed control material dispensing system. The material dispensingsystem of the present invention may be used with other types ofagricultural implements, but is primarily used with seed plantingequipment. Although the FIGURES show a single row of planting equipment,typical planters include multiple rows, up to 24.

The distributed control system consists of a main microcontroller 10which communicates to a plurality of sub-controllers 60. Thesub-controllers 60 implement commands received from the main controlunit 10 by applying electric power to a metering device 72. Thepesticide container 40 contains a memory device 85 for retaininginformation pertaining to the material in the container 40 and to themetering device 72. This information is used by the main control unit 10and the sub-controllers 60 to properly dispense the pesticide.

The material dispensing system shown in the FIGURES is a distributedcontrol system that employs a master microcontroller computer 10 locatedin the operator's cab. Typically, the material dispensing system is usedin conjunction with a seed planter 20 which is attached to and pulled bya farmer's tractor (not shown). Each row of the seed planter 20 includesa seed hopper and seed planting mechanism 30 and a pesticide containerand associated dispensing mechanism 40. Pesticides include, but are notlimited to, insecticides, herbicides, fungicides, fertilizers and otheragricultural chemicals. This master or main controller 10 distributescommand and control information via a high speed serial communicationslink 50 to a plurality of individual meter systems 70. A typicalagricultural planter may have up to 24 rows of seed hopper and seedplanting mechanisms 30 and pesticide containers 40. Each row correspondsto one row in the field being planted. Each individual meter system 70is controlled by its own slave or row controller 60. The meter system 70consists of an electronic memory circuit 80 and a metering or dispensingdevice 72. The meter system 70 is permanently attached to the pesticidecontainer 40. Preferably, the meter system 70 is attached using a knowntamper evident securing system. The row controller 60 includes amaterial flow sensor 62 which is integral with the row controller 60.The material flow sensor 62 detects the presence or absence of flow fromthe pesticide container 40.

The distributed control material dispensing includes a mainmicrocontroller unit 10 with a display 12 and keypad 14 for operatorinterface. A radar 16 is connected to the main control unit 10 toprovide ground speed. Ground speed is used to modify the materialdispensing rate to account for the planter's speed. The main controlunit 10 is connected to a junction box 55 by a high speed serialcommunications link 50. The main controller 10 is in constantcommunication through the serial communications link 50 to the rowcontrol units 60 located on the planter 20.

The row control units 60 allow a method of multiplexing signals going tothe main controller 10. A main benefit is that the main controller 10can control a 24 row planter with only nine wires going to a junctionbox 55. One pair of wires is used for serial communications, three pairsof wires are provided for power to the row control units 60 and to themetering devices 72. One wire is provided for the lift switch 21. Threepairs of wires are used for power to more evenly distribute the currentrequirements.

The main controller 10 also contains a non-volatile memory unit,typically known as "flash" memory. Information pertaining to the usageand application of pesticides is stored in this nonvolatile memory unit.This information is used to prepare printed reports which meet EPAreporting requirements. Currently, farmers prepare these written reportsmanually.

The junction box 55 is connected by additional portions of the serialcommunications link 50 to a plurality of slave or subcontroller units60. Each slave unit 60 is associated with one row of the planter 20, andis therefore referred to as a row control unit 60. The preferredjunction box 55 can connect up to eight row control units 60 to the maincontrol unit 10. If the planter 20 has more than eight rows, additionaljunction boxes 55 are connected in series to the first junction box 55.A lift switch 21 is connected to the first junction box 55. This switchindicates when the planter 20 is not in an operating position. Otherinterfaces to the main control unit 10 may be provided such as serial orparallel links for transmitting information to other computer systems orprinters.

The row control unit 60 has memory devices and logic devices within tomodify and implement the commands from the main controller 10. The rowcontrol unit 60 reads information from a container memory circuit 80attached to the pesticide container 40 and manipulates the commands fromthe main controller 10 to properly operate the metering device 72. Forexample, if the concentration of pesticide on row 1 is different thanthe concentration of pesticide on row 8, the row control unit 60 canmodify the commands of the main controller 10 to properly dispensepesticides from all rows. The row control unit 60 also reads meteringdevice 72 calibration data from the container memory circuit 80 andmodifies the main controller 10 commands to account for differences inperformance of different metering devices.

The row control unit 60 allows the possibility to completely change theprogrammed functions of the main controller 10. As an example, if apre-programmed row control unit 60 is placed on a liquid herbicidesprayer, the main controller 10 would be able to read the dispenser typeinformation and operate as a liquid sprayer controller.

The preferred embodiment shown in the FIGURES uses one row control unit60 to control one metering device and memory unit 70. A row control unit60 can control more than one device, for example, two metering deviceand memory units 70 or one metering device and memory unit 70 and oneseed hopper and seed planting mechanism 30.

Each pesticide container 40 includes a metering or dispensing device 72which allows controlled application rates under different conditions.The metering device 72 described herein is an electromechanical solenoiddriven device for dry granular material. Other type of dispensers may beused for other materials, such as liquids. One type of metering devicefor dry granular material is described in U.S. Pat. No. 5,156,372,Metering Device for Granular Material.

A side view of the metering device and memory unit 70 is shown in FIG.2. A base plate 71 is fastened to the bottom of the pesticide container40. An electromechanical metering device 72 is attached to the baseplate 71. The preferred metering device 72 uses an electric solenoid 74.The solenoid 74 is attached to one end of a pivot bar 75 which pivots onpivot support 77. The other end of the pivot bar 75 is biased intocontact with material dispensing aperture 76 by a spring 78. Thesolenoid 74 is energized by the row control unit 60 to pivot the pivotbar 75 away from the material dispensing aperture 76, thereby allowingpesticide to flow by gravity out of the pesticide container 40.

The solenoid 74 must be sealed from the pesticide. Pesticide enteringthe solenoid 74 can cause its premature failure. The solenoid end of thepivot bar 75, the spring 78 and the connection of the pivot bar 75 tothe solenoid 74 are sealed by a cover (not shown) to prevent entry ofpesticide into the solenoid 74. The preferred method for pivoting thepivot bar 75 and sealing the solenoid cover is to include a roundflexible washer (not shown) in the pivot support 77. This flexiblewasher, sometimes referred to a living hinge, has a small hole in thecenter, smaller than the diameter of the pivot bar 75. The pivot bar 75is inserted through the small hole in the flexible washer. The flexiblewasher allows the pivot bar 75 to pivot and seals the solenoid coverfrom the pesticide.

An electronic memory circuit 80 is connected to the solenoid 74. Amulti-conductor cable 82 and connector 83 are used to connect theelectronic memory circuit 80 to the row control unit 60. In oneembodiment of the present invention, the row control unit 60 directlyapplies electrical power to the solenoid 74 through power wires 81. Inaddition to connecting the row control unit 60 solenoid power to thesolenoid 74, the electronic memory circuit 80 also includes anon-volatile memory device 85. The memory device 85 preferably is an EPROM, a non-volatile memory device that is electrically erasableprogrammable memory, also referred to as EEPROM or E² PROM.

The combination of the electronic memory 85 and the pesticide container40 with attached metering device 72 creates a material container capableof electronically remembering and storing data important to thecontainer, the material dispensing system, and the pesticide. Among thedata which could be stored are: a serial number unique to thatcontainer, pesticide lot number, type of pesticide, meteringcalibration, date of filling, quantity of material in the container,quantity of material dispensed including specific rates of application,fields treated. This stored data can be recalled and updated as needed.The stored data can also be used by a metering controller or pumpingsystem by accessing specific calibration numbers unique to the containerand make needed adjustments, by sounding alarms when reaching certainvolume of pesticide in a container, or keeping track of usage of thecontainer to allow scheduling of maintenance.

An alternate embodiment of the electronic memory circuit 80 includes ameans for blocking the application of electrical power to the solenoid74, to assure that the solenoid 74 is only energized by the materialdispensing system. The electronic memory circuit 80 can include anadditional logic device which will only apply power to the solenoid 74when a permissive control signal or command data is received from therow control unit 60.

In operation, the main control unit 10 receives a desired dispensingrate from the operator via the display 12 and keypad 14. The maincontrol unit 10 monitors the planter's 20 ground speed by the radar unit16. Using the desired dispensing rate, the ground speed and basicdispensing characteristics for the metering device 72, command data forthe row control units 60 are prepared. The preferred dispensing controlfor a solenoid type metering device 72 is to use a fixed rate foractuating the metering device 72, 0.5 seconds, and vary the on time (orduty cycle) of the metering device, 10% to 50%. The row control unit 60modifies the duty cycle specified by the main control unit 10 to accountthe actual metering device 72 calibration data which was retrieved fromthe memory device 85. The row control unit 60 continues to operate themetering device 72 at the rate and duty cycle specified by the maincontrol unit 10 until new commands are received from the main controlunit 10. The main control unit 10 also calculates the quantity ofmaterial remaining in the pesticide container 40.

The row control unit 60 has a flow sensor 62 as part of its electroniccircuits. The flow sensor 62 senses the flow of material from thepesticide container 40. The main control unit 10 can monitor the flowsensors 62 and generate visual and audible alarms as required. The flowsensor 62 consists of an infra-red light source positioned across froman infra-red light detector. These two components are mounted on aprinted circuit board which is part of the row control unit 60. A holeis made in the board between the light source and the light sensor. Thedispensed pesticide is guided through this hole by a light transparenttube. The logic circuit associated with the flow sensor 62 monitors forthe presence of flow by intermittent interruptions of the light reachingthe light sensor. Since the pesticide is dispensed as granularparticles, proper flow will cause intermittent interruptions of thelight. A non-interrupted light will signal no material flowing from thepesticide container 40. A completely interrupted light will indicate ablockage of the tubing after the flow sensor 62.

To operate the material dispensing system, it is necessary for the maincontrol unit 10 to uniquely identify the row control unit 60, meteringdevice and memory unit 70 pairs. Each metering device and memory unit 70includes a unique electronic serial number in the memory device 85. Eachrow control unit 60 also has a unique electronic serial number. When thematerial dispensing system is initialized, the main control unit 10 mustpoll or query all the metering device and memory units 70 and rowcontrol units 60 to determine by serial number which units 70, 60 areattached to the planter 20. This is sufficient identification for thesystem to function. In the preferred embodiment, the operator should beable to refer to a row and its associated seed and material dispensingequipment as row x, rather than by the serial number of the meteringdevice and memory unit 70 or by the serial number of the row controlunit 60. To associate a particular metering device and memory unit 70and row control unit 60 to a particular row, a row configuration methodis provided.

The main control unit 10 is initialized in a configuration mode with norow control units 60 connected. The row control units 60 are thenconnected to the main control unit 10 via the junction box(es) 55 one ata time in the order in which the operator would like them to represent.The first row control unit 60 connected would represent row one. Thisallows an operator who prefers to work from left to right to have theleft most row row 1 and an operator who prefers to work from right toleft to have the right most row row 1.

With a many as 24 rows on a planter 20, it is necessary to control orlimit the current drawn by the metering solenoids 74. If all 24solenoids were operated simultaneously, the current demands could exceedthe capacity of the operator's tractor.

The rate at which the metering device 72 is operated is typically 0.5seconds. The metering device 72 is actually activated at a 10% to 50%duty cycle (10% to 50% of the rate). The solenoid is turned on at 0.5second intervals for 0.05 to 0.25 seconds. The preferred method ofvarying the dispensing rate is to keep the rate fixed and vary the dutycycle. Minimum current demand can be achieved by sequencing theactivation of each metering device 72. The optimum sequence time isdefined as: Rate/Number of Rows. For a 4 row system operating at a rateof 0.5 seconds, the sequence time is 0.125 seconds (0.5 seconds/4). Thismeans that the metering devices 72 are started at 0.125 secondintervals. A variation of this sequencing is to divide the meteringdevices 72 into groups, and stagger the starting times of each group.

The system operates in the following manner: Material dispensing beginswith the main control unit 10 sending each row control unit 60 a "start"command at the appropriate time (the sequence time). The row controlunit 60 does not actually receive and use the sequence time value.Because of variations in the operation of the multiple row control units60, the row control units 60 will drift away from the ideal sequencing.It is necessary to periodically issue a "re-sync" at approximately oneminute intervals and basically restart each metering device 72 whichre-synchronizes each row control unit 60 back to the main control unit's10 time base.

An alternate power sequencing method requires the main control unit 10to send a sequence time or delay time to each row control unit 60. Themain control unit 10 then sends a start command to all row control units60 simultaneously. Each row control unit 60 then activates theassociated metering device 72 after the time delay previously specified.

The material dispensing system features and capabilities include:

Controls application rate of material under varying operatingconditions. The application rate can be set by the operator from anoperator's console or can be automatically read from the materialcontainer meter unit. The later technique offers an advantage in that itdoes not allow the operator to enter an incorrect application rate.

The system will not allow material application if the materialidentification number for all rows do not match. This preventsinadvertent application of two different pesticides.

Provides actual ground speed information if a ground speed sensor isattached. Typical ground speed sensor include wheel rpm and radar. Inlieu of a ground speed sensor, a fixed planting speed may be entered andused to distribute the granular pesticide material.

The system monitors material flow and alerts the operator to no flow,empty container, or blocked flow conditions.

The system monitors and tracks container material level for each row.

The system provides control information and data to a non-volatilememory for future downloading.

The system monitors the planter to allow pesticide to be applied onlywhen the planter is in the planting position.

A typical usage for this system is:

1) For a new pesticide container, the metering device and memory unit 70is attached to the pesticide container 40 by either the containermanufacturer or at the container filling site.

2) A computer is connected to the metering device and memory unit 70 atthe time of filling. The following information is electronically storedin memory device 85:

Date

EPA chemical ID numbers

Container serial number

Suggested, such as ounces per acre for root worm, or ounces per acre forants, etc. These rates are specified by EPA.

Meter calibration information, depending on type of metering device

Tare weight of the container

Weight of the full container

3) The container is sealed and prepared for shipping.

4) The end user, the farmer, buys the chemical container from adistributor. The distributor connects the metering device and memoryunit 70 to a computer and stores the buyer's EPA registration number,distributor's ID number and date in the metering device and memory unit70.

5) The end user takes the pesticide container 40 and attaches todispensing implement, such as planter, sprayer, nurse tank, etc. Themain controller 10 compares the user's EPA registration number with theEPA registration stored in metering device and memory unit 70. If theregistration numbers do not match, the material dispensing system willnot function. The main controller 10 receives the information from themetering device and memory unit 70 pertaining to proper applicationrates and prompts the user to pick the desired rate. The row controlunit 60 reads the metering device calibration information from themetering device and memory unit 70. This information is used incombination with commands from the main controller 10 to properlycontrol the operation of the metering device 72. The main controller 10prompts the user to enter estimated amount of acreage to be covered. Theamount of pesticide remaining in the containers 40 is checked and analarm is generated if the amount in the containers is not enough tocover the estimated acreage. The user them enters a field ID number andany other required information such as number of rows, width betweenrows, etc, The user applies the pesticide to the field. The maincontroller 10 monitors the ground speed and changes the amount beingdispensed to keep a constant rate per acre. When the user finishes afield, additional fields may be treated. Field data, including field IDnumber, crop treated and quantity applied is recorded in the maincontroller's 10 non-volatile memory. This information may also berecorded in the metering device and memory unit 70 for later use by thedistributor or pesticide supplier.

6) The empty or partially used pesticide container 40 is returned to thedistributor. Either the recorded usage information or the current weightof the container can be used to determine a credit for any unusedpesticide.

Having described the invention, what is claimed is:
 1. A method fordispensing dry granular material from a moving agricultural implement,said implement having a main control unit and a plurality ofsub-controllers, one for each of a plurality of dispensing mechanisms,each for dispensing dry granular material directly to a crop row,comprising the steps of:determining a desired dispensing rate;generating command data consistent with the desired dispensing rate tocontrol the actuation of a metering device in each said dispensingmechanism to dispense said dry granular material directly to said croprow; measuring the ground speed of the agricultural implement; modifyingthe command data to account for the ground speed at each dispensingmechanism; receiving stored calibration data for each said meteringdevice from an electronic storage device; further modifying the modifiedcommand data to account for the calibration data of each said meteringdevice; and actuating the metering device in response to the furthermodified command data.
 2. The method, according to claim 1, fordispensing dry granular material, wherein the step of determining adesired dispensing rate comprises:receiving material data from theelectronic storage device, the material data including informationpertaining to type of material being dispensed, permissible uses of saidmaterial, and permissible dispensing rates; and selecting a desireddispensing rate from said permissible dispensing rates.
 3. The methodaccording to claim 1, for dispensing dry granular material, furthercomprising:recording usage data in the electronic storage device, saidusage data being retained for later retrieval and downloading for use inpreparation of environmental reports, the usage data including quantityof material dispensed.
 4. The method according to claim 1, fordispensing dry granular material, further comprising:monitoring the flowof material from each of said plurality of metering devices; andgenerating an alarm upon the cessation of flow from any of saidplurality of metering devices.